Southeast: Caladiums See the Light

Caladiums are old favorites in southern gardens. Like many plants, they also inspire some people to become insane collectors of every available cultivar—I know a gardener in the Low Country of South Carolina who grows about a zillion caladiums every summer. Pots of caladiums cover the porch, driveway, and a specially made caladium bench that wraps around a live oak (pictured). An old swing set has been converted to hold the pots of tissue-thin leaves.

These southern standbys have become more popular around the country in recent years, sparking an interest in developing new cultivars that are adaptable to a wide range of site conditions. For years, our selection of cultivars was limited to varieties developed in the 1950s that require deep shade and lots of water. Since 1976, however, researchers at the University of Florida have been breeding caladiums for tougher conditions and easier care. Many of the new caladiums look like older varieties (in fact, they even carry the old names with ‘Florida’ tacked on—the olive, pink, and white ‘Florida Elise’, or red and green ‘Florida Red Ruffle’), but have thicker leaves, stand up-right nicely, and some, like the red and green ‘Florida Sweetheart’, even take full sun. ‘Florida Fantasy’ produces 15-by-15-inch leaves of white and marbled pink. ‘Florida Calypso’ also sports large leaves, which are swirled with red, pink, and green.

In the interests of science (OK, and my own caladium collection), I tested five of these new varieties in containers on a deck, where they consorted with about 200 other tropical plants for the summer. In each 18-inch container, I planted 10 caladium tubers, two inches below soil level, with lots of dehydrated chicken manure. All the new varieties received four to six hours of direct sun, and although many looked a little wilted in the August afternoon heat, cooler evening temperatures always brought them back to attention.

The next step will be to see how the new cultivars mix with other plants in the garden. I often use caladiums in summer beds, underplanting “annuals”—like ‘Blacky’ sweet potato, ‘Lady in Red’ salvia, and cuttings of silver willow—with a burgundy strap-leaf caladium called ‘Red Frill’. Annuals help the caladiums look more like a natural part of the garden, and they fill in the bare spots until the caladiums emerge, which doesn’t happen until the soil warms up to about 70°F.

Now is the time to see caladiums at their peak, so that when planting time rolls around next April, you’ll know exactly which varieties to add to your garden.

To do in the garden

If crinum, ginger, or canna leaves start to look a little peaked, cut them back to the ground and water the plants well. New foliage will grow rapidly and look great by the time cooler autumn days roll in.

Direct sow nasturtiums for decorative foliage and flowers from now until Thanksgiving.

Cut back late-flowering, giant perennials such as swamp sunflower (Helianthus angustifolius) if you want them to flower at a shorter height than normal.

In a designated bed, start seeds of biennials such as parsley, tall bellflower (Campanula americana), and verbascum. These will be ready to move into the garden by October.

Worth growing

Crinum ‘Ellen Bosanquet’

This is an investment perennial—it may not be a standout garden specimen for the first few years, but for decades thereafter it will be stunning. Its enormous bulb (sometimes as big as a volleyball) sends up a fountain of glossy, kelly-green foliage and a four-foot-tall scape of as many as 12 flowers that open in succession, from May until October (but mostly in midsummer). ‘Ellen’ performs best in full sun to part shade, with small, winter-growing companions like arums or asarums to fill in space when the bulb goes dormant. Hardy to USDA Zone 7.